Posted
by
Unknown Lamer
on Tuesday November 27, 2012 @03:09AM
from the missed-a-spot dept.

coondoggie writes "Sandia National Laboratories physicist Willis Whitfield, 92, passed away earlier this month and left a technological legacy that continues to reverberate today: The legendary clean room. The original laminar-flow 10 x 6 clean room developed 50 years ago by Whitfield was more than 1,000 times cleaner than any cleanrooms used at the time and ultimately revolutionized microelectronics, healthcare and manufacturing development. According to Sandia, with slight modifications, it is still the clean room standard today."

I used to work for a company that made microchip inspection machines and they had a "clean" room. Things go so unclean that everyone in the building had to have a re-education class in clean room even if there was no chance they would ever be in one. It was that bad.
People wouldn't wipe their feet, wear masks, hair covers, etc. But what I think really, really pushed management over the edge and require classes for *everyone* was people were not only eating potato chips in there but leaving the wrappers. That, was the last straw.

Cleanrooms are pretty much dead technology. I work in one of the few large-scale 'real' cleanrooms left (100k+ square feet at class <10), which was built in the mid 90s.

200mm wafers were small enough for people to carry around and material handling robots were less advanced, so it made sense to make the entire fab into laminar-flow cleanroom and have people carry wafers around exposed to the air. This is obviously absurdly expensive, given the square footage of HEPA filters and sheer air-moving horsepower needed.

Now, a full lot of 300mm wafers is too heavy for a person to carry around all day, cleanliness standards are higher, and material handling robots are cheap enough to replace humans. The new fabs store all wafers in sealed plastic FOUPs which are robotically delivered to each process tool. Only the inside of the positively-pressurized process tools has to be truly clean. The big squirrel-cage VLF fans have been replaced by an array of axial fans covering the roof that can be individually tweaked and adjusted to optimize airflow and power.

Companies still pretend it's a cleanroom and force people to wear smocks out of habit, but most of them are only held to class 10,000 or so, which is cleaner than your living room but not clean enough to make wafers in, without the FOUPs.

My father was an engineer for Western Electric and I remember him telling me many years ago about a MIG pilot that defected with the plane. Our guys were surprised to find that the advanced fighter used tubes in it's avionics. It was determined that the Soviets couldn't put together a good enough clean room to produce chips.

indeed, in space technology, you definitely use cleanrooms everyday, class 10,000 or more for 'ordinary' telecom satellites, but as low as class 100 for everything optics (military or civilian).And I can tell you, class 100, it's something.In my factory we have a variable-class optics integration room, hundred metres sized, where a constant laminar airflow going from left to right actually separates one class-100 end, on one side, from the other end which stays 10,000 -a nice trick that allows you designer to enter the room without turning into a cosmonaut, and quietly discuss the instrument integration details with the actual cosmonaut, almost face to face, just separated by 15m of (clean) air...